/*---------------------------------------------------------------------------*
  Project:  NitroSDK - GX - demos - UnitTours/Sub_CharBg_3
  File:     main.c

  Copyright 2003,2004 Nintendo.  All rights reserved.

  These coded instructions, statements, and computer programs contain
  proprietary information of Nintendo of America Inc. and/or Nintendo
  Company Ltd., and are protected by Federal copyright law.  They may
  not be disclosed to third parties or copied or duplicated in any form,
  in whole or in part, without the prior written consent of Nintendo.

  $Log: main.c,v $
  Revision 1.8  2004/04/07 01:23:27  yada
  fixed header comment

  Revision 1.7  2004/04/06 12:48:06  yada
  fixed header comment

  Revision 1.6  2004/02/24 05:25:21  yasu
  used OS_EnableIrqMask instead of OS_SetIrqMask

  Revision 1.5  2004/02/18 01:09:52  yasu
  added comment for code32.h

  Revision 1.4  2004/02/12 07:06:27  nishida_kenji
  avoided generating STRB in THUMB mode

  Revision 1.2  2004/02/05 07:09:03  yasu
  changed SDK prefix iris -> nitro

  Revision 1.1  2004/02/02 06:24:44  nishida_kenji
  based on 2D_CharBg_3

  $NoKeywords: $
 *---------------------------------------------------------------------------*/

//---------------------------------------------------------------------------
// A sample that uses BG #2 as affine mode (scaling):
//
// USAGE:
//   UP, DOWN, LEFT, RIGHT: Change the center position of scaling
//   A,B:                   Scaling BG #2
//
// HOWTO:
// 1. Set up the character/palette/screen data same as Sub_CharBG_1.
// 2. Set up a matrix and points by G2S_SetBGxAffine().
//---------------------------------------------------------------------------

#include <nitro/code32.h>	// avoid byte access problems
#include <nitro.h>
#include "DEMO.h"
#include "data.h"

#define STANDARD_SIZE        (1 << 8)

static u8 sScrnBuf[SCREEN_SIZE];                           // Buffer for screen data (BG #2)

void NitroMain(void)
{
    s16 x_0 = 0, y_0 = 0;
    s16 x_1 = 0, y_1 = 0;

    fx32 scale = 1 << FX32_SHIFT;

    //---------------------------------------------------------------------------
    // Initialize:
    // They enable IRQ interrupts, initialize VRAM, and set BG #2 for affine mode.
    //---------------------------------------------------------------------------
    DEMOInitCommon();
    DEMOInitVRAM();
    DEMOInitDisplaySubBG2Only();

    //---------------------------------------------------------------------------
    // Transmitting the character data and the palette data
    //---------------------------------------------------------------------------
    GXS_LoadBG2Char(d_64_256_bg_schDT, 0, sizeof(d_64_256_bg_schDT));
    GXS_LoadBGPltt(d_64_256_bg_sclDT, 0, sizeof(d_64_256_bg_sclDT));

    {
        int i, j;
        for (i = 0; i < 8; i++)
        {
            for (j = 0; j < 8; j++)
            {
                sScrnBuf[(i * 16) + j] = (u8) ((i * 0x10) + j);
            }
        }
    }
    // Store the data onto the main memory, and invalidate the cache.
    DC_FlushRange(sScrnBuf, sizeof(sScrnBuf));
    
    // DMA Transfer to BG #2 screen
    GXS_LoadBG2Scr(sScrnBuf, 0, sizeof(sScrnBuf));

    DEMOStartDisplay();
    //---------------------------------------------------------------------------
    // Main Loop
    //---------------------------------------------------------------------------
    while (1)
    {
        MtxFx22 mtx;
        fx32 rScale;

        DEMOReadKey();
        if (DEMO_IS_PRESS(PAD_KEY_UP))
            y_0 -= 2;
        if (DEMO_IS_PRESS(PAD_KEY_DOWN))
            y_0 += 2;
        if (DEMO_IS_PRESS(PAD_KEY_RIGHT))
            x_0 += 2;
        if (DEMO_IS_PRESS(PAD_KEY_LEFT))
            x_0 -= 2;
        if (DEMO_IS_PRESS(PAD_BUTTON_A))
            scale -= 2 << (FX32_SHIFT - 8);
        if (DEMO_IS_PRESS(PAD_BUTTON_B))
            scale += 2 << (FX32_SHIFT - 8);
        if (DEMO_IS_TRIG(PAD_BUTTON_SELECT))
        {
            x_0 = 32;
            y_0 = 32;
            scale = 1 << FX32_SHIFT;
        }

        rScale = FX_Inv(scale);
        mtx._00 = rScale;
        mtx._01 = 0;
        mtx._10 = 0;
        mtx._11 = rScale;
        
        SVC_WaitVBlankIntr();                              // Waiting for the end of V-Blank interrupt

        //---------------------------------------------------------------------------
        // Set up affine transformation for BG #2
        //---------------------------------------------------------------------------
        G2S_SetBG2Affine(&mtx,                              // a matrix for rotation and scaling
                         x_0, y_0,                          // the center of rotation
                         0, 0                               // the reference point before rotation and scaling applied
                         );
    }
}

//---------------------------------------------------------------------------
// V-Blank interrupt function:
//
// Interrupt handlers are registered on the interrupt table by OS_SetIRQFunction.
// OS_EnableIrqMask selects IRQ interrupts to enable, and
// OS_EnableIrq enables IRQ interrupts.
// Notice that you have to call 'OS_SetIrqCheckFlag' to check a V-Blank interrupt.
//---------------------------------------------------------------------------
void VBlankIntr(void)
{
    OS_SetIrqCheckFlag( OS_IE_V_BLANK );                   // checking V-Blank interrupt
}
